@Jason – Google’s V8 engine is, I believe, a lot more comprehensive than what you see in Firefox, and I suspect that’s why they’re providing access through Javascript. I suspect what we’ll see is a lot more Chrome V8 templates created, giving a lot of surface area for Javascript extensions, once they get basic functionality out.

Jason Knight, actually, Greasmonkey was released first (version 0.2.5, April 2005), before Opera 8.0 b3 which introduced that feature. Greasmonkey was apparently directly inspired by a site-specific extension (see http://wiki.greasespot.net/Greasemonkey) in 2004. But Opera’s support had been in production for the year previous to release, and had been in discussion at Opera since 2002 (see http://operawiki.info/UserJS#interlude).

So, Opera was working on the feature itself longer, but Firefox was designed to use Javascript under the hood, so it was simpler to implement and got it first.